$-efg + 9f + 9g - 9 = f + g + 5$ Solve for $e$.
Explanation: Combine constant terms on the right. $-efg + 9f + 9g - {9} = f + g + {5}$ $-efg + 9f + 9g = f + g + {14}$ Combine $g$ terms on the right. $-efg + 9f + {9g} = f + {g} + 14$ $-efg + 9f = f - {8g} + 14$ Combine $f$ terms on the right. $-efg + {9f} = {f} - 8g + 14$ $-efg = -{8f} - 8g + 14$ Isolate $e$ $-e{fg} = -8f - 8g + 14$ $e = \dfrac{ -8f - 8g + 14 }{ -{fg} }$ Swap the signs so the denominator isn't negative. $e = \dfrac{ {8}f + {8}g - {14} }{ {fg} }$